VO₂-assisted multifunctional metamaterial for polarization conversion and asymmetric transmission

A VO₂-assisted temperature-controlled multifunctional metamaterial polarization converter with large asymmetric transmission (AT) is proposed by introducing a gold-VO₂ grating. The converter can be switched between reflection mode and transmission mode by controlling the phase transition. When VO₂ is in the metallic state, the converter works in reflection mode, converting the incident forward/backward linearly/circularly polarized waves into the cross-polarized waves, and the broadband polarization conversion rates (PCRs) can reach 90% with relative bandwidth of up to 91.1% and 87.5%, respectively; when VO₂ is in the insulating state, the converter shows giant AT effect for circularly polarized waves at 0.64 THz and 1.28 THz. The multifunctional polarization converter holds great potential in the fields of communication and imaging, which provides a new way to design optical devices such as polarizers, isolators.